This invention relates to para ordered aromatic dicarboxylic acids containing benzimidazole groups.
In general, the class of aromatic heterocyclic extended chain polymers are well known for their outstanding thermal, physical and chemical properties. These polymers generally exhibit excellent modulus and tenacity properties.
Tsai et al, U.S. Pat. No. 4,892,921, disclose that the aromatic heterocyclic extended chain polymers lack good properties when in compression. Tsai et al disclose para-ordered aromatic heterocyclic extended chain polymers having pendant benzoxazole and benzothiazole groups which have good properties when in compression.
Arnold et al, U.S. Pat. No. 4,892,953, disclose phenylbenzthiazole-substituted diacid terphenyl monomers which are used for making aromatic heterocyclic extended chain polymers which exhibit improved compressive properties.
We have prepared new para-ordered aromatic diacids containing benzimidazole groups. Benzimidazole-pendant polymers prepared from these diacids, when treated with phosphoric acid, form stable benzimidazonium cations. The acid treated polymers exhibit improved thermooxidative stability as compared to alkaline treated polymers.
Accordingly, it is an object of the present invention to provide novel para-ordered aromatic diacids containing benzimidazole groups.
It is another object of the present invention to provide methods for preparing these para-ordered aromatic diacids containing benzimidazole groups.
Other objects, aspects and advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the invention.